Going to Kunming soon to see my Girlfriend which is the best Visa to get?

What does your GF do in Kunming? If she studies or works there for long time, then you are able to acquire long-term stay after you get married. If you visit her for the first time, then you just need to apply for a tourist type.

However, your problem is that I am not sure if you can get married in Kunming if both of you are foreigners.